A container joined only to an intern network gets no default route
(network_join.cpp), so pinging a real outside address (8.8.8.8) must
fail outright, not merely succeed slower than an extern join would.
Verified end-to-end as root: both variants correctly report
"Network unreachable" and the tests assert a RESULT= line was seen
(the command actually ran) that isn't RESULT=0.
First of a planned series of end-to-end -n/--network join tests
(tests/integration/test_network_join_scenarios.cpp, [integration][root][net]):
two containers joined to the same intern network ping each other by IP,
run once with a real veth pair and once forced onto the tap+relay
fallback, since the two are genuinely different implementations. IPv6 is
deliberately excluded pending a known device-specific peculiarity.
split_lines_trimmed()/extract_marked_lines() moved from
test_rootless_run.cpp into tests/support/fixtures.{h,cpp} for reuse here.
wait_for_eth0_then() wraps a sandboxed command's own network-touching
script in a poll for eth0 to exist first: join_networks() runs
concurrently with, not before, the sandboxed command starting, so a
near-instant command can otherwise exit before its own join finishes --
the exact limitation already documented in network_join.{h,cpp}'s own
CLAUDE.md entry. Confirmed by testing (not assumed): without this, the
container's own immediate ping-and-exit sometimes raced ahead of the
veth-move step, which then failed outright ("Invalid netns value")
against an already-exited pid.
ceamac